Brunhes–Matuyama reversal

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The Brunhes–Matuyama reversal, named after Bernard Brunhes and Motonori Matuyama, was a geologic event, approximately 781,000 years ago, when the Earth's magnetic field last underwent reversal.[1][2] Opinions vary as to the abruptness of the reversal: it may have occurred over several thousand years,[3] or much more quickly,[4][5][6] perhaps within a human lifetime.[7]

The apparent duration at any particular location varied from 1,200 to 10,000 years depending on geomagnetic latitude and local effects of non-dipole components of the Earth's field during the transition.[3]

The Brunhes–Matuyama reversal is a Global Boundary Stratotype Section and Point (GBSSP), selected by the International Commission on Stratigraphy as a marker for the beginning of the Middle Pleistocene, also known as the Ionian Stage.[8] It is useful in dating ocean sediment cores and subaerially erupted volcanics.

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References[edit]

  1. ^ Gradstein, Felix M.; Ogg, James G.; Smith, Alan G., eds. (2004). A Geological Time Scale 2004 (3rd ed.). Cambridge University Press: Cambridge University Press. p. 28. ISBN 9780521786737. 
  2. ^ "Global chronostratigraphical correlation table for the last 2.7 million years". International Commission on Stratigraphy. Retrieved 31 March 2014. 
  3. ^ a b Bradford M. Clement (8 April 2004). "Dependence of the duration of geomagnetic polarity reversals on site latitude". Nature 428 (6983): 637–40. Bibcode:2004Natur.428..637C. doi:10.1038/nature02459. PMID 15071591. 
  4. ^ Witze, Alexandra (Sep 2, 2010). "Geomagnetic field flip-flops in a flash". ScienceNews. Retrieved 3 September 2010. 
  5. ^ Coe, R.S.; Prévot, M.; Camps, P. (20 April 1995). "New evidence for extraordinarily rapid change of the geomagnetic field during a reversal" (PDF). Nature 374 (6524): 687. Bibcode:1995Natur.374..687C. doi:10.1038/374687a0. 
  6. ^ Bogue, S. W.; Glen, J. M. G. (2010). "Very rapid geomagnetic field change recorded by the partial remagnetization of a lava flow". Geophysical Research Letters 37: L21308. Bibcode:2010GeoRL..3721308B. doi:10.1029/2010GL044286. 
  7. ^ Leonardo Sagnotti, Giancarlo Scardia, Biagio Giaccio, Joseph C. Liddicoat, Sebastien Nomade, Paul R. Renne, Courtney J. Sprain; (21 July 2014). "Extremely rapid directional change during Matuyama-Brunhes geomagnetic polarity reversal". Geophys. J. Int. 199 (2): 1110–1124. doi:10.1093/gji/ggu287. 
  8. ^ "Global Boundary Stratotype Section and Point". International Commission of Stratigraphy. Retrieved 31 March 2014. 

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